Gyroscopic compass



Sept. 16, 1941. E; P, Regs 2,255,899

GYROSCOPIC COMPASS Filed Jan. 11, 1959 '2-Sheets-Sheet 2 IN VEN TOR Eilliottl. ROSS ATTORNEY Patented Sept. 16, liidl I V GYROSCOPIC COMPASS Elliott r. Ross, Forest Hills, N. r., assignor to Ford Instrument Company, Inc.,

Long IslandOity N. Y., a corporation of New York Application January 11, 1939, Serial No. 259,28!

Claims.

The invention herein disclosed relates to gyroscopic compasses and more particularly toa compass of this type wherein thecustomary pendulous gravity control is replaced by a suitable control from a stabilized base, and still further the invention relates to a compass adapted to having the axis of the gyroscope maintained continuously parallel to the axis of rotation of the earth or in a plane containingsaid axes.

It is a well known scientific fact that if a gyroscope be balanced in neutral equilibrium and mounted so as to relieve it, of all disturbing influenccs and then set it in'spaee, for example,

' with its axis parallel to the earth's axis of rotation, that it will retain this direction in space regardless of its position on the earth; Under these conditions the spin axis of they compass gyroscope will point to the pole of the heavens, and indicate not only the true north but the latitude of the place. If these conditions could be fulfilled, such a gyroscope would be the ideal compass.

The present gyroscopic compasses however are maintained with the axis of' their gyroscopes tangent to the earth's surface by the use of gravity pendulous devices. These compasses when on the equator are not disturbed by the rotation of the earth when they are on the the spin axes of their gyroscopes are then parallel to the axis of the earth. However, as these compasses are moved to a position north or south of the equator, their gyro axes are no longer parallel to the earth's axis and the rotation of the earth causes them to depart from the meridian. Consequently various forms of compensating devices :are necessary to correct for the error commonly known as the latitude error.

meridian, since It is an object of the present invention to provide a gyroscopic compass which will rapidly seek the meridian and when on the meridian is not subject to disturbing forces such as are produced in pendulous gyroscopic compasses by acceleration forces due to; roll and pitch; and changes of speed and course of the ship.

It is another object of the present invention to eliminate the errors due to the eflect of the rotation of the earth and movement relative to the earth, by maintaining the compass gyro-v scope axis parallel to the earth's axis at all latitudes.

It is a further object of the invention to eliminate the disturbing forces on the gyroscopic compass due to the pendulum customarily used,

by the substitution therefor of a gyroscopic stabilized base or frame.

In accordance with the invention these objects and-certain advantages which will hereinafter appear are accomplished by taking advantage of the phenomenon described above.

By elevating the control for the compassgyroscope axis to an angle equal to the latitude, if north of the equator, and depressed if south of the equator, the axis of the gyroscope oLthe compass is maintained continuously parallel to the earth's axis instead of being'maintained tan gent to the earth's surface. The disturbing forces on the gyroscopic compass areeliminated by the use of a g'yroscopic stabilized base or frame. It is desirable that this base be of the type controlled by a pendulum'to determine the vertical and compensated for accelerations.

The angular movement of the axes of these compasses to maintain them horizontal as they'are moved in a north-south direction causes a further tendency to depart from the meridian generally known as the north-south steaming error. The pendulums used to maintain the gyro axis horizontal introduce additional errors since they are disturbed by acceleration forces due to roll and pitch, changes of speed, and ,course of the ship. In accordance with one of the fundamental principles of the gyroscopic compass the north end of the gyro axle tends to fall due to the-rotation of the earth, when it is westof the meridian and rise when it is east of the. meridian. The useof this phenomenon to bring the gyro axis to'the meridian is well known and is .most pronounced when the compass is at the equator. I

This base has a power-driven element for apply. ing precession-inducing forces to the compass gyroscope so that these forces may react against this element but not directly on the stabilizing gyroscope. Such a base is disclosed in U. S. patent to Gillmor et 111., 1,984,874.

The invention will now be more particularly described by reference to the embodiment musvtrated in the drawings, and will be hereinafter pointed out in the claims.

In the accompanying drawings:

Fig. 1 is an isometric elevation illustrated somewhat diagrammatically of a gyroscopic com pass and mechanism embodyingthe invention;

' Fig. 2 is a sectional view taken along the line 2-2 ofFig.1; v

Fig. 3 is. a sectional view partly broken away taken along the line 3-4 of Fig. 1;

Fig. 4 is an enlarged sectional view taken. along the line 4-1 of Fig. 1;

- tion; and

of a gyroscopic compass A and a scope frame 2. The standards la and lb areso and 3d from the lower ends of which are susend to the rod l4 for movement about the verv r In, order to take advantage use this principle to maintain the axis of V Fig. 5 is an enlarged side view'partly broken away, showing another form of spring vconneciFig. 6 is a wiring diagram showing the operation ofvthe follow-up systems in Fig. .1. V

The mechanism illustratedin Fig. 1 consists bilized base or support B.

The base :3 consists of a pair of standards la' and lb which are permanently secured to'the deck of the ship upon which the mechanism is mounted. In the construction illustrated in Fig.

gyroscopic stain the plane of the meridian; a mechanism in the form of an adjustable carriage 25,-hereinafter I to be described, is provided with an adjustment so that the carriage may be positioned with reference to the gyro in accordance with the latitude of the ship. The mechanism accomplishing this adjustment applies .a precession-inducing force 7 on the gyroscope to keep it in 'theplaneof the meridian. In. the disclosed embodiment of the 1 the standards la and lb formbearingsi'or trunnions 2a and 2b that extend from a gyropositioned that the axes of the trunnions 2a'and 2b of the frame are parallel to the fore and art line of the ship. Within the frame 2there1 is mounted a ring 3. The ring 3 has trunnions 9a and 3b thatare journaled in the frame 2. the axes of these trunnions being athwartship or at an angle of 90 to the trunnion axis of the frame 2-. Integral with opposite points of the lower edge of the ring 3 are downwardly extending arms 3c pended a gimbal ring 4 which carries agyrosc'ope journaled near the ends of the arms to and 9d respectively, and the gyroscope 5 is mounted for 5. The ring 4 has trunnions 4a and 4b that are i oscillatory movement about the trunnions Ia and so 5b joumaled in the gimbal ring 4. Integral With the upper edge ofthe ring} and disposed atlan angleor 90 from the arms and 3d, are upwardly extending arms 9e and 3f which'are joined together at their upper and approximately mid section points by integral portions 6 andl,

respectively, to form a frame 8. I 3

The gyrcscopic compass A consists of avertical gimbal ring 9. a vertical or driven ring III, a

gyroscope ll mounted for oscillatory movement 40 within thering 9, and a compass card l2. As

shownmore clearly in Fig. 2, the compass card l2 has a hollow integral hub l9 which fits over one end of a rod l4 and to which it is secured 'i' means of a pin l5. This rod is .f ournaled for rotatable movement with the compass card in a boss it on the part 6 of the frame I and another boss I! on top of the ring 9. .The other endoi. this rod is .securedto the drivenring III by means of a pin l9. The lubber's point, or the point in- (mating the. ship's head. is represented by the upper end l9 of a rod 29 secured to the frame 8.

I The vertical gimbal 9 is rotatably mountedlfor 'movementabout a vertical axis A'-- A', the upper end formovement, about the rod l4 by means of the journal in the boss n. and the lower end by means of a' boss 2| iournaledto receive a trunnion 22' which is secured by, a pin 29 to a boss 24 on the part I of the frame 8. The driven rin It, as already mentioned. is secured at its pper ticalaxis with the compass card, andthe lower end is 'pivotally mounted on the trunnion 22. The gyroscope. II is rotatably mounted within the gimbal ring 9 for movement about trunnions li and .l lb which are journaled in the gimbal ring 9. Hubs ll'c and lid of the gyroscope ll,

- as shown in Fig. 1, have their axes in the northsouth plane.

of the fundamental f principle of ,the gyroscope, that the north end of the axle of the gyroscope tends to fall due to the rotation of the earth when west of the meridian and rise when it is east of 'themeridian, andto' invention the point of 1 application or the precession-inducing force on the gyroscope is shown as being substantially inline with the spin axis. t

However, the point of application may be at other points on the gyro casing as long as the force is exerted aboutthe-trunnion axis Ila-l lb. To

accomplish this-the hub He at the north endof' t the gyroscope ll is connected by means ofv a spring I le to the carriage 25. I v h The driven ring ill of the gyroscope II is fitted on its outer surface with a rack 26. As shown more clearly in Fig. 4, the adjustable carriage 25 consists of an inner portion 21 and an outer portion 28, dovetailed and secured together by means of screws 29 and 30. The inner sides of the carriage 25 slidablyengage the outer and inner edges of the driven ring ill. The outer por tion 28 is journaled at each end to receive a rotatable shaft 3| which carries a pinion 32 secured to the shaft by means of a pin 33. At

one end of the shaft Si is secured by means '01.

a pin 34, a distance piece 35, and secured to the a other end by means of a pin. 38, is the knob 31. The knob 91 operates the shaittl and thepinion 92 which meshes with the rack26, on the driven ring ill. .The connection 0! the spring I le with the carriage 25 isshown at- 39. 'On turning the knob 31 the carriage '25 is moved up or down along the'ring III, in accordance with the latitude. The position of the carriage 25 may be adjusted manually by means or the knob 31 in accordance with the latitude of the position of the ship, or automatically-by connecting the. knob with the latitude dial of a dead reckoning mechanism.

The need for the customary latitude corrections I due to the rotation of .the earth is not present because the axis of the hubs lie and lid of the motor 40, controlled by means of electrical contacts 39. The follow-up motor is mounted on and secured to the part 6 of the frame 9 by means of a bracket 4|. The contacts 39, see Fig. 6, include a pair of spaced electrically insulated contacts 390: and 39b that are mounted on a bracket 42, secured to the ring ill, by means of anarm 49, and a roller contact that is mountedon 'a bracket integral with thegimbai ring 9 ofthe gyroscope ll. As relative move ment between the gimbal ring 9 and-the ring Ill occurs about the axis A' -A',' the contact 44 rides ofi the central insulated section betweenthe contacts 39a and 39b and onto cheer the other of the contacts. Such contact between the conw tacts 44 and 39a or 99b causes the operation of I the gyro '4 the motor 40, by electrical connections, hereinafter to be described and shown in Fig. 6, to drive the ring III in a direction to restore the proper angular relationship between the gimbal ring 6 and the driven ring I. This is effected by means of a pinion 46 secured to one end of a 5 shaft 41 and driven by the motor 46. The pinion 46 meshes with gear teeth 46 on the periphery of the compass card I2. Since the compass card is connected to the driven ring III by means of the rod I4, movement of the motor 46 is communicated to the ring III. The other end 46 of the motor shaft 4'! is connected by means of bevel gears 66 and 5| to a transmitter 62 by means of which the heading of the ship is communicated to compass repeaters.

To effect the operation of the follow-up motor 46, as shown in Fig. 6, a wire 63 connects one side of the motor to a line wire 64. The contacts 69a and 36b are separately. connected to the motor through wires 56 and 56 respectively, and the roller contact 44 is connected by means of a wire 51 to the other line wire 66.

Since the construction of the stabilized base B is well known in the art and may be of the type described and shown in the above mentioned patent, only such parts have been illustrated in the drawings that are pertinent to this invention.

The description therefore of the base B will be limited to the manner in which it cooperates as a whole in the combination in which it occurs with the other elements in this invention. R,eferring again to Fig. 1 the operating mechanism of the base will now be briefly described. The stablilized base B is utilized to maintain the frame 6 and consequently the gyroscopic ably compensated for the forces due to accelerations such as are produced by change of course and speed of the ship as described and illustrated in the above mentioned patent. As the ship rolls and pitches, motor operated follow-up mechanisms cooperate to maintain the ring 3 continuously horizontal and the axis A'-A parallel to the axis of the gyroscope 5 in the following manner.

Movement of the gyroscope 5 about the axes 5a and 5b relative to the, gimbal ring 4 controls the movement of the frame 2 about the trunnions 2a and 2b. This movement of the frame z is effected through a follow-up motor- 59 and electrical contacts 60. The follow-up motor 66 60 is connected to the frame'2 through a worm 6| mounted upon a shaft 62 of the motor 66 and a segmental worm gear 66 integral with the frame 2. The worm gear 63 is concentric with the trunnion axis of the frame 2. The contacts 66 include a pair of spaced, electrically insulated contacts 66a and 6012 (Fig. 6) that are mounted on a bracket .64 secured to the gimbal ring 4,

' and'a' roller contact 66c that is'mounted on a 70 *bracket 65 secured to the casing of the gyroscope 5. In order to prevent any torque producing pressure being applied to the gyroscope 6 by the contact device 66, the contacts 66a and 6612 are formed into a curved surface, the center of the radii of curvature of which is in the axis 604?).

To eifect the operation of. the motor 66 a wire.

66 connects one side-of the motor to a line wire 64. The contacts 66a and 66b are separately connected to the motor through wires 61 and 66 respectively and the roller contact 660 is connected by means of a wire 66 to a line wire 66. Mounted on the shaft 62-betwe'en the motor 66 and the worm 6| is a gear III which meshes with a gear H mounted on a shaft {12 of a transmitter 16. It will be understood that the motor 56, worm 6| and transmitter I6 with the connecting shaft and gearing are suitably mounted on the standard In by mountings not shown.

' As relative movement between the gyroscope 5 and the gimbal ring 4 occuisabout the trunnions 6a and 6b, the contact 660 rides off of the central 'insulatedsection between thecontacts66a and 66b and on to one or the other of the contacts. Such contact between the contact 66c and the contact 600 or 66b causes the operation of the motor 66 to rotate the frame 2 about the axis 2a and 2b in a direction to restore the proper angular relationship between the gimbal ring 4 and the gyroscope I. This movement of the frame 2 is communicated to the ring 6 by means of the trunnions 6a and to the gimbal ring 4 by the arms 30 and 6d by means of which the ring 4 is supported.

Similarly, movement of the gyroscope 6 and the 'gimbal ring 4. about the trunnions 4a and 4b relative to the ring 6 controls the movement of the ring 6 about the trunnions 3a and 6b. This movement of the ring 6 is effected through a follow-up motor 14 and electrical contacts 16.

The follow-up motor 14 is connected to drive thering 6 as follows: a gear '16'mounted on the shaft 11 of the motor meshes with a gear 16 connected to one side of a compensating difo ferential I6; theother side of the differential is r connected to a gear 66 freely mounted on shaft 6| and meshing with a gear 62 secured to one end of a shaft 66; on the other end of the shaft 83 is secured a bevel pinion 64 which mesheswith the arcuate rack 66 mounted on the arm Seof the frame 6; the shaft 6| is secured at one end to the spider 66 of th differential I6 by 'a pin 19;: and at the other end carries a gear 61; the gear 61 meshes with a gear 66 integral with the trunnion 2b of the frame 2; the trunnion 2b is journaled to receive the shaft 66 freely rotatable therein. It will be seen that as the frame Zrotates relative to'the standard lb, the gear 64 will be rotated therewith, through the oompensating differential 16, by means of thegears 66 and 61, the shaft", spider 66, gearsflli, 62 and the shaft 66. Mounted on the shaft "between the motor and the gear 16 is a gear 66 which meshes with a gear 66 vmounted on the shaft 6| of a transmitter 62. It will be understood that the motor 74, transmitter 66, differential 19, associated shafts and gearing are suitably mounted on the standard lb by mountings not shown. The electrical contacts 76 include a roller 16a (Fig. 6) that is mounted on the bracket 64 which is secured to the gi bai ring 4 and two spaced electrically insulated contacts 15b and lie thatare mounted on a bracket 66 secured to the arm 6d near its lower end. To

effect the operation of the motor 14, the contacts 76b and are connected to the motor by I wires 64 and 66 respectively. The common'of the motor |4 is connected to the negative line wire 64' by a conductor 66 and the other line bal ring 4 and the ring 3 is maintained.

- continuously vertical.

- gather to maintain another object remotely situ It will be apparent "the axis of the gyroscope].

' I I with the-adjustable carriage. The outer mem-' 5 associated with the spring members and these membersresist any tendency of the lug I06 to 45 bers 9 and I00. Larger departures from the reaction thereof will cause ,the compass to rapidlyprecess to the meridian.

wire 501s connected by a conductorll to the; contact 1511. Q 1

1 As relative movement between the gimbal ring I I and. the ring .3 occurs about the 'trunnions 4a and); the roller 15a rides upon one or the other 1 of the contacts 15b or lie and effects operation? of the motor 14. The operation of the motor 1.4 rotates the ring 3 about the a'xisjila and3b and the proper angular relationship between the gim-i 10 From the foregoing it, will be seen that the: ring 3 corresponds at alltimes with the gyro-' scope 5. Since the spin axis of the gyroscope; is verticalthe ring 3 will be horizontal and represent a true horizontal. plane. Consequently,

the axis A'-A of the gyroscope A,is maintained.

The transmitter 13 transmits the motion due?v to the roll of the ship and the transmitter 921 transmits the motion due to the pitch of the ship, and these motiom. may be combined to-1 ated in a true horizontal plane. that instead of a compos-j ite unit as shown, the, compass A may be sepa-I rated from the stabilized mount 3 to form separate units with appropriate connections tov maine tain the axis A'-A' vertical, that is, paralleito In .Fig'. 5 is shownva preferred form. of Spring connection between the gyroscope II and the x driven ring I0. Upper and lower spaced spring leaf members,'in pairs, '90, 99 and I00. IOI are secured by screws I02to a bracket I03 integral ber of each pairof these springs, or the members' 9,0 and MI, are made of heavier material than that of the inner members 99 and I00. The

outer spring members are separated from the inner members by distance pieces I04 andI05 40 A. lug I00 integral with a bracket I061; is secured by screws I01 and I00.to the hub lie of the gyroscope II, The lug I08 is operatively change its position relative to the carriage 25. In accordance with one of the fundamental principles .of the g'yroscopic compass already described, that the north end of the axis of the gyroscope tends to" fall due to the rotation oi the earth when. west of the-meridian and rise when it is east of the meridian: if the axis of the gyroscope departs from the meridian toward the eastthus causing the hub IIcuto rise; the lug I06 will contact one of the upper pair of spring members; the reaction of the spring will cause the gyroscope .II to, precess in a direction which .will return the axis to the meridian. Simi- 'larly, departures west of the meridian will cause :the. hub No to fall,-sothat the lug I00 will con-H tact one of the lower spring members. The reaction of the spring will cause the gyroscope to precess in a direction which will retumthe axis to the meridian." Any-tendency for small;,departures from'the meridian on the part. of the axis will be resisted by the smaller spring mem-.

meridian, however, such as would'occur in starting up the compass, will cause the heavier springs "and IM to come into action, whereupon the 7 V It will be" apparent to those that the heavy spring members 08 and I0,I may skilled in the at fie. so proportioned as to rapidly precessv the i 2,256,899 g r gyroscope on to" the meridian due to the effect,

1 N maintains the of the-rotation of the earth on the gyroscope. With the axis of. the gyroscope parallel to the earth's axis, as illustrated in'the preferred embodiment of the invention, the precession of the .compass' gyroscope 'due to the rotation of.- the earth'will cease. In consequence thereof, :10 damping or correcting mechanism .is necessary to prevent the tendency of the gyroscope to 'wander. to apply small processing forces once scope is substantially on the meridian, to maintain it them against any tendency there might be to wander due to friction in the hearings or other extraneous -,forces.- a Y It will be seenvthat the seek the meridian on departure therefrom. The

follow-up contacts. 39a andg39b are so con- 1 nected and arranged that the follow-up motor fixed relationship, and the departure from this relationship is never sufficient to permit any appreciable torque to be produced about the vertical axis .e'A' by the spring IIe. Consequently the only effective torque applied to the gyroscope by the spring lie. is about the hon- .zontalaxis Hat-Ill), the same as the torque applied by the leaf spring members of Fig. 5. Asalready described, relative movement between the gimbal' ring 0 andthe driven-ring I0,

produced by the precession of the gyroscope back to the meridian or change of course of the ship,

actuates the follow-up. motor 40, by means of which these rings are maintained in fixed rela-' tionship about the axis A'-A',and the compass card is operated to continuously indicate the 'true heading of the ship. 7 The driven ring I0 is graduated in degrees, and

fractions thereof, oflatitude, and the position of the can'iage may be adjusted manually by means of the knob 31, 01 automatically, by connecting the knob 31 with the latitude dial of a dead reckoning device. Thesetting of the carriage may be read through an opening orwindow I09 in the carriage 25.

It will be obvious that various changes may be made by those skilled in. the art in the details of the embodiment ofthe invention disclosed in the drawings and described above within the principle and scope of the invention as expressed v in the appended claims.

I claim: t '1 1. In a gyroscopic compass, the combination of a stabilizing gyro-vertical adapted to maintain a horizontal plane, a universally mounted frame. power-driven follow-up means controlled by said gyro-vertical for driving said frame in accordanceiwith the position of the gyro-vertical to maintain said frame horizontal, a compass gyroscope pivoted for three degrees of freedom I in said frame, 'a ring mounted in said frame adapted toangular movement about a 'vertical axis, and precession-inducing means connected to the ring and to thegyroscope adapted to restore the axis of said gyroscope to the meridian plane upon angular movement of the gyroscope relative to the frame, due'to the departure of the gyroscope axis from the meridian plane. 2. In a gy'roscopic tain-a horizontal plane, a universallyv mounted frame, power-driven Iollow-up-means controlled The light springs and I00 are provided I v the gyrooperation of the spring I I la of Fig. 1 will be eflective in a similar manner to cause the axis of the gyroscope to rapidly rings 9 and Min a'relatively compass, the combination I oi a stabilizing, gyro-vertical adapted to main- 7 2,255,899 by said gyro-vertical for driving said frame in cent above and below. said lug and at yarious accordance with the positions of the.gyro-ver' distances therefrom so as to be progressively tic-a1 to maintain said frame horizontal, a comengaged by said lug when the gyroscope tilts pass gyroscope pivoted for three degrees of freethe members closest to the, said lug being of dom in said frame, a ring mounted in said lighter construction than that oi the other memframe adapted to angular movement about a, bers, and means for sliding the carriage along vertical axis, and precession-inducing means the ring to adjust the anguiar position of the adapted to keep the spin axis 01' the gyroscope spin axis of the gyroscope relative to the ring, in the plane of the meridian including a memsaid means being settable in accordance with the bet connected to the said ring and settable" 10 latitude.

thereon in accordance with the latitude and 5. In a gyroscopic compass, the combination resilient means connecting the said member with of a power-driven horizontally stabilized frame the gyroscope. containing a compass mechanism mounted in I 3. In, a mechanism of the type described for the stabilized frame, said mechanism includadjusting the spin axis of a gyroscopic compass, 15 ing a compass gyroscope pivoted forthree dethe combination with a compass gyroscope havgrees of freedom including angular movement is three degrees of freedom, of a Vert al ring about a normally vertical axis, a power-driven for the gyroscope extending about the tilt axis ring mounted concentrically with the tilt axis of the gyroscope, a canine slidably mounted on of the gyroscope for angular movement about the ring, a sp in inter onn c ng the carriage 20 the said vertical axis, precession-inducing means and the gyroscope at a point fixed to and lying interconnecting said compass gyroscope ,and substantially in the spin s of he gyroscope. I said ring, including yieldable means connected ea o Sliding e carriage 810118 t ng to said gyroscope and to said driven ring and t adius h an ular p sit n-oi th spin axis .settable circumferentially or said ring in acof the gyroscope relative to th n sa d m ans 25 cordance with the latitude for maintaining the being settable in accordance with the latitude. spin axis of the said gyros cope in the plain: 1n-

4. In a mechanism f h e described for cluding the location and the axislof the earth adjusting the spin axis of a yros pie c p at the set latitudes, power-driving means for the,combination with a compass gyroscope havthe driven ring and contact control means on the 1118 three degrees of freedom and a 1 8 on the 3 said ring and the said gyroscope for controlling casing thereof along the axis of spin, of a vertical the power-driving means whereby the driven ring extending concentrically about the tilt axis ring is maintained in a plane containing the of the gyroscope, a carriage slidable along the spinaxis of the said gyroscope.

ring, a plurality of spaced spring leaf members 1 1 ELLIOT! P. ROSS. connected with the carriage and disposed adia- I i 

